problem: how to handle concurrency problem using yield? And the problems encountered.(from lecture 5)
yield(): suspends the running thread, chooses a new thread to run, and resumes the new thread
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yield(): acquire(t_lock) // Suspend the running thread id = cpus[CPU].thread threads[id].state = RUNNABLE threads[id].sp = SP threads[id].ptr = PTR // Choose a new thread to run do: id = (id + 1) mod N while threads[id].state != RUNNABLE // Resume the new thread SP = threads[id].sp PTR = threads[id].ptr threads[id].state = RUNNING cpus[CPU].thread = id release(t_lock)
